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JAVA：RMI回調->對象已導出

[英]JAVA: RMI Callback -> object already exported

 原文  2015-06-12 17:20:27  6   1    java/ callback/ server/ rmi/ stub

問題描述

這是我的第一個問題，對不起，如果我將其設為不正確，請說英語。

我必須用Java做一個分布式hang子手項目，這里有客人，玩家和主人（更多比賽）。 當用戶（已經注冊）登錄自己或主服務器打開比賽時，服務器必須將所有事件通知給所有訪客（僅訪客）。 在客戶端中，我必須創建2個存根，其中1個用於服務器，另一個用於圖形界面（swing）。

線程池用於管理比賽，現在不使用。 這是客戶端代碼： 

package User;

public class Utente extends RemoteServer implements UserInterface, GraphicInterface,Serializable {

private static final long serialVersionUID = 2L;
private String name;
private String password;
private String host = "localhost";
private Socket soc;
private int port = 1800;
private UserInterface stub = null;
private RegistryInterface server_interface = null;
private Registry server_registry;


public Utente(){
    super();
    this.name = "user";
    this.password = "passwd";
    //per connettersi al server
    try {
        server_registry = LocateRegistry.getRegistry(host);
        server_interface = (RegistryInterface)server_registry.lookup("HANGMAN-SERVER");
    } catch (RemoteException | NotBoundException e) {
        System.out.println("errore connessione lato client");
        e.printStackTrace();
    }
    //per l' rmi con la gui

}


public synchronized boolean login(String n, String p) throws RemoteException {
    boolean esito = false;
    export();
    esito = server_interface.login(n,p,stub);
    return esito;
}

public synchronized boolean logout() throws RemoteException {
    boolean esito = false;
    esito = server_interface.logout(name,stub);
    return esito;
}

public synchronized void notifyMatch(ArrayList<Partita> lista_partite) throws RemoteException {
    if(lista_partite!=null){
        if(lista_partite.size()==0){
            System.out.println("Ancora nessuna partita aperta.");
        }
        else{
            for(int i = 0;i<lista_partite.size();i++){
            System.out.println(lista_partite.get(i).getNameMatch());
            }
        }
    }
}

public void connect(){
    try {
        soc = new Socket(host, port);
    } catch (UnknownHostException e1) {
        e1.printStackTrace();
    } catch (IOException e1) {
        e1.printStackTrace();
    }

}


public static void main(String[] args) {
    Utente user = new Utente();
    Registry c;
    GraphicInterface stubExport = null;
    try{
        stubExport = (GraphicInterface)UnicastRemoteObject.exportObject(user,3900);
        LocateRegistry.createRegistry(5000);
        c=LocateRegistry.getRegistry();
        c.rebind("GraphicUI", stubExport);
    }
    catch (RemoteException e) {
        System.out.println("errore nel client: " + e.toString());
    }
    MainPanel startPanel = new MainPanel();
    startPanel.setVisible(true);    
}



}

錯誤清單： 

UI export problems
java.rmi.server.ExportException: object already exported
    at sun.rmi.transport.ObjectTable.putTarget(Unknown Source)
    at sun.rmi.transport.Transport.exportObject(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.exportObject(Unknown Source)
    at sun.rmi.transport.tcp.TCPEndpoint.exportObject(Unknown Source)
    at sun.rmi.transport.LiveRef.exportObject(Unknown Source)
    at sun.rmi.server.UnicastServerRef.exportObject(Unknown Source)
    at java.rmi.server.UnicastRemoteObject.exportObject(Unknown Source)
    at java.rmi.server.UnicastRemoteObject.exportObject(Unknown Source)
    at User.Utente.export(Utente.java:59)
    at User.Utente.login(Utente.java:100)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$254(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$1/1989325584.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at registry.Server.callbackClient(Server.java:189)
    at registry.Server.login(Server.java:201)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$254(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$1/1786588690.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
    at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
    at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
    at sun.rmi.server.UnicastRef.invoke(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
    at com.sun.proxy.$Proxy0.login(Unknown Source)
    at User.Utente.login(Utente.java:101)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at sun.rmi.transport.Transport$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$254(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$1/1989325584.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
    at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
    at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
    at sun.rmi.server.UnicastRef.invoke(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
    at com.sun.proxy.$Proxy1.login(Unknown Source)
    at gui.MainPanel$2.actionPerformed(MainPanel.java:110)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$500(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

感謝您的耐心等待，我希望這個問題能夠順利解決。 我知道代碼很丑陋，時間不多，我也做了很多修改。

1 個解決方案

解決方案1
 0 已采納  2015-06-12 20:54:23

可能是，我想我在您的Utente類中發現了錯誤。 您已在代碼中的2個位置導出了對象，這導致java.rmi.server.ExportException:object already exported.

在您的Utente的main（）方法中， 

stubExport = (GraphicInterface)UnicastRemoteObject.exportObject(user,3900);

其中user是Utente類的對象。

另外，在同一類的login（）方法中，您正在調用export（）方法，該方法包含： 

stub = (UserInterface) UnicastRemoteObject.exportObject(this,0);

在這里， this將與Utente當前正在調用的對象有關，在這種情況下，該對象將是user ，該對象已被較早導出。

因此，似乎您將對象導出兩次，導致拋出異常。

請答復是否有幫助。 祝好運！

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